I have a 97' e320 with 110k miles that has recently started to, what seems to be, misfire when it gets to about 3500 rev's. It starts and runs fine at lower rev's but as soon as it gets to the higher rate in kick-dowm or fixed gear mode it has a problem. Any ideas anyone ?? Last service 6 months ago had the plugs, filters, etc changed so I don't think it's anything related to those parts. I did change the battery 1 month ago and discovered that a multitude of things need resetting - is there anything I've missed that may be related to the problem ??